Nothing 'Puny' about this...

Work is underway on a challenging project in Norfolk, which involves changing the flow on a 3.5km fenland waterway called the Puny Drain.

The objective is to relocate the outfall and install a partially pumped system to improve drainage in the Puny Drain's catchment. The current outfall, located in Kings Lynn and discharging to the River Great Ouse, is being moved 4km inland. Challenges along the way include creating a new permanent road bridge over the drain, and getting it underneath a railway line and under the River Nar.

"The railway line will be traversed by sinking two 7.5m diameter by 12m deep shafts each side of the track," explains Malcolm Bear, General Manager. "A pumping system will then lift water into the first chamber and allow it to siphon under the rail line through two 1.5m pipes, which connect the two chambers some 10m below the track.

"We will then take Puny Drain under the Nar by installing a 2.1m culvert some 6m below ground level, and 4m below the existing river," Malcolm Bear adds.

The road bridge will be installed over Thiefgate Lane before the drain meets the Great Ouse, where the new outfall will be constructed through the flood embankment.

The new channel is programmed to be commissioned in August, which will complete the first phase of the project. Phase two will be to infill the original outfall in Kings Lynn with around 60,000 cubic metres of stabilised material.